"What is a completely ordinary, harmless thing that instantly makes you irrationally suspicious of someone?"

[Cassy micheal]

We all have that one weird little mental shortcut. Maybe someone tells you they hate all music, or they leave their phone face-up on the table when they're talking to you, or they eat a KitKat without breaking it apart first. It doesn't mean they're a bad person—it just short-circuits your brain for a second and makes you think, "What else are you hiding?"
I'll start: If someone tells me they "just don't really watch movies or TV shows," I immediately feel like I'm talking to an undercover android. Like, what do you do with your evenings? Stare at a blank wall and calculate prime numbers?
What’s your totally unfair, harmless red flag?